Signs, in particularly signs that are used in buildings with multiple tenants, are known to have a frame with replaceable sign strips for ease of replacement. For example, FIG. 1 shows a prior art wall-mounted sign system that has a pair of wall mounted columns 20 adapted to allow the directory panel or sign strips 22 to be clamped thereon via brackets 24 attached to the back of the strips. The sign strips in this example have to be removed from the top one by one, such that if a strip from the bottom of the stack of strips needs to be changed, all the strips have to be removed by sliding upwards from columns 20.
In another prior art example as shown in FIGS. 2A and 2B, The sign strips 26 are mounted onto the wall-mounted column 28 via clips 30 that have a cross-section shape generally of a semi-circle. The sign strips 26 have flanges 32 adapted to grip onto the clips. These strips may be plugged out from the columns individually from the front, but due to wide flanges 32 used for mounting to the clips 30, a big gap has to be provided between sign strips to provide sufficient space for access and removal from the front 26a 
In some prior art methods the sign strips are difficult to mount and demount, while in other prior art methods, the signs are too readily pried off.